High voltage double break interrupter switch



July 24, 1962 H. w. GRAYBILL 3,046,365

HIGH VOLTAGE DOUBLE BREAK INTERRUPTER SWITCH Filed June 19, 1958 3Sheets-Sheet 1 July 24, 1962 H. w. GRAYBILL HIGH VOLTAGE DOUBLE BREAKINTERRUPTER SWITCH 3 Sheets-Sheet 2 Filed June 19, 1958 I I H H H H HWIJuly 24, 1962 H. w. GRAYBILL HIGH VOLTAGE DOUBLE BREAK INTERRUPTERSWITCH Filed June 19, 1958 5 Sheets-Sheet 3 INVENTOR. H0 mzeo mafinra/zab lt Anne/145%! drawn and extinguished simultaneously.

United rates 3,946,355 Patented July 24, 1962 time , The instantinvention relates to interrupter switches in general and moreparticularly to an interrupter switch wherein two serially connectedarcs are drawn simultaneously.

Single throw interrupter switches, using a quick-break blade in anarc,chute of gas-evolving material as the interrupting means, have beenwell-known in the industry for nearly two decades. However, many testshave shown that a single break interrupter of the gas-evolving type willinterrupt only a few amperes at potentials above 15 kv. Other types ofinterrupters are available for service in the 15-33 kv. range, but theyare either more complicated or more expensive to manufacture than thearc chute interrupter.

I propose to provide a switch with an arc chute interrupter of thegas-evolving type, suitable for interrupting load current in the orderof 400 amperes at voltages in the order of 33 kv. Tests have shown thathigher voltages can be interrupted successfully if two series arcs areHowever, if the two arcs are not drawn simultaneously, the firstinterrupter will attempt to interrupt the circuit unsuccessfully, andthe advantage of the second interrupter is lost. The construction of mynovel double-break interrupter switch is such that the two series arcsmust inherently be drawn simultaneously.

I Briefly my invention comprises a main blade and a quick-break bladeboth mounted for rotation about a common pivot which is positionedmidway between two stationary contact assemblies. A torsion springinterconnects the blades and urges the quick-break blade about the pivottoward a first stop carried by the main blade. The stationary contactassemblies each include restraining contacts, engageable with separateends of the quick-break blade, and an associated arc chute of gasevolving material.

p In order to open my switch the main blade is rotated. However, therestraining contacts exert a force upon the quick-break blade whichtends to maintain it in the closed position. Thus the initial rotationof the main blade will cause the' torsionspring to be loaded. When themain bladereachesa predetermined angular position a second stop mountedthereon engages the quick break blade with a rigid mechanical connectionand thereafter forces it to rotate in unison with the main blade.

. After a relatively short movement of the quick-break blade it is freeof the restraining contacts and, once free thereof, the loaded torsionspring takes over to rapidly rotate the quick-break blade toward thefirst stop. Thus serially connected arcs are drawn simultaneously ineach arc chute which decompose a portion of the arch chute walls therebyabsorbing energy from the arcs to cool, deionize and otherwise bringabout the rapid extinguishing of the arcs.

Accordingly, a primary object of my invention is to provide a novelinterrupter switch of the arc chute type, in which series arcs are drawnin such a manner that the arcs are inherently simultaneous.

Another object is to provide an interrupter switch in which two seriesarcs are drawn in separate interrupters, with a common acceleratingspring to separate the contacts in both interrupters.

Still another object is to provide an interrupter switch in which twoseries arcs are drawn in separate interrupters,

with a common quiclobreak blade being the moving member in bothinterrupters.

A further object is toprovide a disconnectingswitch of the double-breaktype, with an arc chute type interrupter mounted at either stationarycontact, arranged to draw simultaneous series arcs in, the two arechutes.

These as well as other objects of the instant invention shall becomereadilyapparent after reading the following description of theaccompanying drawings in which:

FIGURE 1 is a side elevation of my novel interrupter switch.

FIGURES 24 are plan views of the interrupter switch ofFlGURE 1. InFIGURE 2 the interrupter is fully closed, in FIGURE 3 is is shown justprior to the movement of the quick-break blade, and in FIGURE 4 theinterrupter is fully open.

, FIGURE 5 is across-section taken through line 5-5 of FIGURE 4 lookingin the direction of the arrows to illustrate the restraining contacts. I

Referring tothe figures, interrupter switch 16 comprises a pair ofstationary contact assemblies 11,12 mounted on insulator standoffs 13,14, respectively, and a movable blade assembly mounted on insulator 16.

'- Insulators 13, 14 are rigidly secured to channel base 17 whileinsulator 16 is positioned midway between insulators 13, 14 and isrotatably mounted to base 17 in bearing 18. 7

Each of the stationary contact assemblies 11,12 are comprised of 'a maincontact 20 and restraining contacts 21 mounted to bracket 22. Bolts 23secure contact 20 and bracket 22 to their associated fixed insulators 13and 14. Main contacts 2% extend beyond their respective insulators 13,14- to form switch terminals 23, 24, respectively. Arc

' chutes 25 are secured to brackets 22 in operative position toextinguish arcs drawn at restraining contacts 21.

The restraining contacts 21 (FIGURE 5) are each mounted at the ends ofindividual flexible contact clips 99 which are biased toward one anotherby means of coil springs 98. Clips 99 are disposed between a pair of fanrivets 93.

Main contacts 20 are positioned for engagement'by a'main blade :which iscomprised of two elongated members 27, ZSrigidly secured by means ofstuds 26 to the upper end of insulator16. Washers are secured to bothends of members 27 and 28 to supply contact' pressure against the maincontacts 20. Ring 29 acts as a spacer to separate members 27, 28 so thatmain contacts 20 may be sandwiched therebetween.

Quick-break blade 31: is an elongated member whic is secured to shaft 32which is pivotally mounted to insulator 16. Shaft 32 is in alignmentwith shaft 33 about which insulator 16 is pivotable. Torsion spring 34is wound about shaft 32 and has one end secured to insulator 16 and theother end secured to quick-break blade 31 thereby biasing quick-breakblade 31 clockwise, with respect to FIGURE 2, toward engagement withstop 35 mounted on main blade member 27.

, Restraining contacts 21 engage quick-break blade.31 with a forcesufficient to maintain interrupter 10 closed regardlessof the loadingupon accelerating spring'34. It is only when there is a rigid drivingconnection between rotatable insulator 16 and quick-break blade 31 thatuick-break blade "31 may be separated from restraining contacts 21. Therigid driving connection issupplied by a) stop 36 secured to the lowermember 23 of the main blade.

Switch is operated from the closed position (FIG- URE 2) to the openposition (FIGURE 4) rotating insulator 16 clockwise with respect toFIGURE 2 by applying an opening force thereto through crank 37 by meansof a suitable actuating mechanism of conventional design. The initialrotation of insulator 16 carries main blade 27, 28 clockwise to anintermediate position (FIG- URE 3) thus separating main blade 27, 28from stationary main contacts 29. However, arcs are not drawntherebetween since the circuit is still completed through quickbreakblade 31.

In moving to the intermediate position insulator 16 loads acceleratingspring 34 but this loading is insufiicient to separate quick-break blade31 from arcing restraining contacts 21. Upon further rotation of mainblade 27, 23 from the intermediate position (FIGURE 3) toward the openposition (FIGURE 4), stop 36 provides a driving mechanical connectionbetween insulator 16 and quick-break blade 31 which is greater than therestraining forces exerted by arcing contacts 21 so that the ends ofquick-break blade 31 become separated from restraining contacts 21. Assoon as blade 31 is separated from contacts 21, the loaded acceleratingspring 34 takes over to rapidly rotate quick-break blade 31 clockwiseinto engagement with stop 35.

As quick-break blade 31 rotates under the influence of spring 34, arcsare simultaneously formed between the ends of blade 31 and theassociated restraining contacts 21. The heat of the arcs decomposeportions of the walls of arc chutes causing dielectric gases to beevolved therefrom. This decomposition of the walls absorbs energy fromthe arcs, thereby efiiciently cooling, deiouizing and extinguishing thearcs.

Closing of switch 10 is accomplished by rotating insulator 16 from theposition of FIGURE 4 to the position of FIGURE 5. Stop 35 provides arigid driving connection between insulator 16 and quick-break blade 31so that blades 31 and 27, 28 move in unison in a counterclockwisedirection until the ends thereof engage the stationary contacts 21 andZtl, respectively.

Thus I have provided a novel construction for a high current, highvoltage interrupter switch of the arc chute type in which seriallyconnected arcs are simultaneously drawn resulting in improved circuitinterruption.

Accordingly, I prefer to be bound not by the specific disclosureherewith but only by the appending claims.

Iclaim:

1. An interrupter switch comprising a first and a second stationarycontact assembly, a movable blade assembly operatively positioned withthe opposite ends thereof engageable with said first and said secondcontact assemblies respectively, said blade assembly being rotatableabout an axis positioned midway between said contact assemblies therebyassuring that arcs drawn at said contact assemblies will besimultaneously created; said movable blade assembly comprising a mainblade, a quick-break blade, and a torsion accelerating springoperatively connected between said blades and mounted concentricallywith respect to said axis of said blades and operatively positioned tourge said blades toward a predetermined angular first position withrespect to one another; said switch being operable between an open and aclosed position by rotation of said blade assembly about said axis; bothof said blades being in engagement with said contact assemblies whensaid switch is in said closed position; said switch being moved fromsaid closed to said open position by a rotation of said blade as semblyin a first direction; said contact assemblies comprising first means forrestraining rotation of quickbreak blade during initial rotation of saidmain blade through a predetermined angular distance in said firstdirection; said means being overcome after said initial rotation ofpredetermined angular distance and said accelerating spring thereafterrapidly rotating said quick-break blade to said first position; secondmeans carried by said main blade engageable with said quick-break bladeafter said initial rotation; said second means comprising a rigid armsecured to and mounted transverse to said main blade and having aflanged end adapted to abut said quickbreak blade upon rotation of saidmain blade through said predetermined angular distance for rotation ofsaid quick-break blade; said second means providing a driving connectionbetween said blades for overcoming said restraining means and rotatingsaid quick-break blade in said first direction; each of said stationarycontact assemblies including a main contact, engageable with said mainblade, an arcing contact, engageable with said quick-break blade, and anarc chute operatively positioned to receive an arcdrawn between saidarcing contact and said quick-break blade upon operation of saidinterrupter to its open position; each of said are chutes comprising apair of gas evolving plates positioned substantially to the plane ofmovement of said quick-break blade.

2. An interrupter switch comprising a first and a second stationarycontact assembly, a movable blade assembly operatively positioned withthe opposite ends thereof engageable with said first and said secondcontact assemblies respectively, said blade assembly being rotatableabout an axis positioned midway between said contact assemblies therebyassuring that arcs drawn at said contact assemblies will besimultaneously created; said movable blade assembly comprising a mainblade, a quick-break blade, and an accelerating spring operativelyconnected between said blades and mounted concentrically with respect tosaid axis of said blades and operatively positioned to urge said bladestoward a predetermined angular first position with respect to oneanother; said switch being operable between an open and a closedposition by rotation of said blade assembly about said axis; both ofsaid blades being in engagement with said contact assemblies when saidswitch is in said closed position; said switch being moved from saidclosed to said open position by a rotation of said blade assembly in afirst direction; said contact assemblies comprising first means forrestraining rotation of quick-break blade during initial rotation ofsaid main blade through a predetermined angular distance in said firstdirection; said means being overcome after said initial rotation ofpredetermined angular distance and said accelerating spring thereafterrapidly rotating said quick-break blade to said first position; secondmeans carried by said main blade engageable with said quick-break bladeafter said initial rotation; said second means comprising a rigid armsecured to and mounted transverse to said main blade and having aflanged end adapted to abut said quick-break blade upon rotation of saidmain blade through said predetermined angular distance for rotation ofsaid quickbreak blade; said second means providing a driving connectionbetween said blades for overcoming said restraining means and rotatingsaid quick-break blade in said first direction; each of said stationarycontact assemblies including a main contact, engageable with said mainblade, an arcing contact, engageable with said quickbreak blade, and anarc chute operatively positioned to receive an are drawn between saidarcing contact and said quick-break blade upon operation of saidinterrupter to its open position; a first insulator having said firstcontact assembly secured thereto and a second insulator having saidsecond contact assembly secured thereto; a third insulator having saidblade assembly mounted thereon; said third insulator being positionedmidway between said first and said second insulators and being rotatableabout said axis; said main blade being rigidly secured to said thirdinsulator for rotation in unison therewith; each of said are chutescomprising a pair of gas evolving plates positioned substantially to theplane of movement of said quick-break blade.

3. An interrupter switch comprising a first and a sec ond stationarycontact assembly, a movable blade assembly operatively' positioned withthe opposite ends thereof engageable with said first and said secondcontact assemblies respectively, said blade assembly being rotatableabout an axis positioned midway, between said contact assemblies therebyassuring that arcs drawn at said contact assemblies will besimultaneously created; said movable blade assembly comprising a mainblade, a quickbreak blade, and an accelerating spring operativelyconnected between said blades and mounted concentrically with respect tosaid axis of said blades and operatively positioned to urge said bladestoward a predetermined angular first position with respect to oneanother; said switch being operable between an open and a closedposition by rotation of said blade assembly about said axis both of saidblades being in engagement with said contact assemblies when said switchis in said closed position; said switch being moved from said closed tosaid open position by a rotation of said blade assembly in a firstdirection; said contact assemblies comprising first means forrestraining rotation of said quick-breakblade during initial rotation ofsaid main blade through a predetermined angular distance in said firstdirection; second means for overcoming said first means after saidinitial rotation of predetermined angular distance; said second meanscomprising a rigid arm secured to and mounted transverse to said mainblade and having a flanged end adapted to abut said quick-break bladeupon rotation of said main blade through said predetermined angulardistance for rotation of said quick-break blade; said acceleratingspring thereafter rapidly rotating said quickbreak blade to said firstposition; said accelerating spring being loaded during said initialrotation of said main blade; a first and a second arc chute fixedlymounted and operatively positioned with respect to said first and saidsecond stationary contact assemblies so as to receive and aid in theextinction of electric current arcs drawn between the ends of saidquick-break blade and said stationary contact assemblies upon opening ofsaid switch.

. another; said switch being operable between an open and a closedposition by rotation of said blade assembly about said axis both of saidblades being in engagement with said contact assemblies when said switchis in said closed position; said switch being moved from said closed tosaid open position by a rotation of said blade assembly in a firstdirection; said contact assemblies comprising first means forrestraining rotation of said quick-break blade during initial rotationof said main blade through a predetermined angular distance said firstdirection;

second means for overcoming said first means after said initial rotationof predetermined angular distance; said second means comprising a rigidarm secured to and mounted transverse to said main blade and having aflanged end adapted to abut said quick-break blade upon rotation of saidmain blade through said predetermined angular distance for rotation ofsaid quick break blade; said accelerating spring thereafter rapidlyrotating said quick-break blade to said first position; saidaccelerating spring being loaded during said initial rotation of saidmain blade; at first insulator having said first contact assemblysecured thereto and asecond insulator having said second contactassembly secured thereto; a third insulator having said blade assemblymounted thereon; said third insulator being positioned midway betweensaid first and said second insulators and being rotatable about saidaxis; said main blade being rigidly secured to said third insulator forrotation in unison therewith; an arc chute fixedly secured to each ofsaid first and said second insulators and operatively positioned toreceive j and extinguish electric current arcs formed between the endsof said quick break blade and said contact assemblies upon opening ofsaid switch.

References Cited in the file of this patent UNITED STATES PATENTS I688,583 Bassert Dec. 10, 1901 1,656,399 Steinmayer Jan. 17, 19281,843,052 Upton Jan. 26, 1932 2,308,026 Rawlins Jan. 12, 1943 2,399,485Harlow et al. Apr. 30, 1946 2, ,3 2 Pl G ----=4--- 9. 5

